checkboxes within paragraph margins

[Jan00]

I would like to create a checkbox (cb) in the left or right margin of numbered and non-numbered paragraphs.

For example:

cb 1. Text text text text text text text.
cb Text text text text text text text.
or
1. Text text text text text text text. cb
Text text text text text text text. cb

(I use FrameMaker +SGML 6.0.)
Thanks.